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To be successful in optics, an understanding of certain basic mathematical principles is essential. If you are concerned about math, don't be. If you can add, subtract, multiply, and divide you will do fine in this section. Algebra In algebra, all numbers are preceded by either a plus (+) sign or by a minus (�) sign. In optics, all prescriptions must also be preceded by a sign. It is never enough to say that a person is wearing 2.00 diopter lenses. It must always indicated if they are +2.00 diopter lenses or –2.00 diopter lenses. The same is true in algebra, the sign must always be indicated before the number. Addition Of Two Plus Numbers: The answers are always plus. Examples:
May Also Be Written: +2.25
+ 1.50 = +3.75
+1.75 +2.50
= +4.25 Addition of Two Minus Numbers: The answers are always minus. Examples:
May Also Be Written: -2.00 -1.50
= -3.50 |
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